(1) Field of the Invention
The present invention relates to a physiological signal detection method, particularly for one of non-contact method for detecting physiological signal and motion in real time.
(2) Description of the Prior Art
Following with the progress of the times, people pay more attention to the daily life of self-health management so that the real-time detection of various physiological signals to assess the physiological state becomes prerequisite, in which the heart rate is one of important health indicators. Currently heart rate detecting methods can be divided into two categories of contact and non-contact detecting methods. For contact detecting method, it is performed in vitro mode with adhesive electrode pad(s) or detecting device(s) worn on the human body to be detected. For non-contact detecting method, it is normally based on the camera to capture images of the human body to analyze volumetric measurement of a blood vessel for optically obtaining a plethysmogram, which is referred as photoplethysmogram (PPG).
Generally speaking, the contact detecting method requires a lot of medical supplies such as pads, disinfection appliances. In addition to the issues caused by cumbersome pasting process of electrode pad or wound wire, there are also some problems such as susceptible to allergic reactions to infection caused by exposure, especially for baby due to more delicate skin. Therefore, the contact detecting method is neither suitable for long-term clinical monitoring nor applying to the wound skin.
Conversely, comparing to the contact detecting method, the non-contact detecting method does not have these problems aforesaid. However, for non-contact detecting method, the photoplethysmogram (PPG) is more susceptible to minor fluctuation incurred by external noise such as movement of body and change of ambient light sources so that the photoplethysmogram (PPG) is difficult to accurately interpret signal(s) in analysis and calculation.
In view of this dilemma issue abovementioned, the non-contact physiological signal detecting system with features in reducing the quantity of processing data/information and enhancing the accuracy of physiological signal(s) detection becomes the future trend in research and development field.